AA 643 then QR 8187 at O'Hare
Los Angeles → Chicago → Houston
Timetable, Chicago time
17:59AA 643 from Los Angeles at the gate
16:40QR 8187 to Houston leaves the gate
22 h 41 apart on the timetable, overnight
QR 8187 leaves 22 h 41 after AA 643 arrives on the timetable: more than half a day, so not a connection we count.